Unified Tow Brake help wanted

Thanks for the reply. No solution yet, but here is where I am at.

I have changed the coach unit, car solenoid and cable (I found a complete new system at a reasonable price), but the problem is still there. So by elimination, it must be the power unit PM6001 that goes into the car. Unfortunately, the new unit has a fault (brake light disabling relay doesn't open), so I haven't been able to swap this out. AP Products are sending another PM6001, so when it arrives I will try it.

Watch this space.

Thanks, Paul.

JCM wrote:
I have been having a problem where the solenoid wouldn't retract any more but with a tech supports help we isolated (I hope) to a defective computer box - by measuring voltages to the solenoid. He said that that the solenoid almost never fails and that sounds so in your system. The only 2 other parts would be the controller on your dash and the computer box under the dash.
If your brake away switch activates what you say I would think it is the darn computer.
If you are in the US Amazon has them for about $319.00.
I would spend the time and phone the company. Keep calling until you get a human.
He was really helpful and I hope when my new computer arrives it will fix my problem.
Good luck - it is a great system when working. Again reviewing your problem I am inclined to also question your dash unit since I believe that is the component that sets the proportional braking.
Let us know the results.